A qualified retirement plan is an investment plan offered by an employer that qualifies for tax breaks under the Internal Revenue Service (IRS) guidelines. An individual retirement account (IRA) is not offered (with the exception of SEP IRAs and SIMPLE IRAs) by an employer. Therefore it is not a qualified plan.
The answer depends on the context in which the term is being used. Usually "qualified retirement plan refers only to employer plans qualified under section 401(a) (which includes 401(k) plans), governmental 403(b) plans, 457(b) plans and the federal TSP. When these types of plans are lumped together with IRAs the group is usually referred to as "qualified retirement accounts." Just to keep things interesting, though, in some contexts the term "qualified retirement plan" is used interchangeably with the term "qualified retirement account" to refer to the entire group including IRAs.